Safety and Efficacy of Panhematin™ for Prevention of Acute Attacks of Porphyria

This is a double-blind, randomized, placebo-controlled, parallel group trial investigating the efficacy and safety of Panhematin™ for preventing acute attacks in at least 20 subjects with well-documented acute porphyria (acute intermittent porphyria, hereditary coproporphyria or variegate porphyria). Subjects will (1.) have had frequent attacks in the past, with symptoms such as abdominal, back and/or limb pain and diagnosed after exclusion of other causes, and (2.) be on hemin prophylaxis for prevention of frequent attacks. It is expected that they will have had 6 or more attacks in one year before starting hemin prophylaxis. This would be considered justification for a preventive regimen of hemin on clinical grounds. Double blind Panhematin™ or placebo will be given. The number of doses will correspond to the number of doses that a subject receives in approximately one week for their prophylactic regimen. An interim analysis will be carried out after completion of 10 subjects to assess progress and possibly adjust the sample size. The trial consists of the following visits:

• A screening visit to determine eligibility and obtain informed consent.
• A treatment visit for administration of double blind prophylactic doses of Panhematin™ or placebo corresponding to the number of doses the subject receives for their prophylactic regimen within approximately one week.
• Follow up visit at 1, 2, 3, and 4 weeks to assess response to the infusion of Panhematin™ or placebo. These visits will be in person or by telephone.
• Additional visits may be scheduled if needed, for example for treatment of symptoms.
• Follow-up visits 3 and 6 months after the end of treatment either in person or by telephone Subjects will have laboratory documentation of one of the acute porphyrias. Molecular documentation is also expected, although rarely a causative mutation cannot be detected. Upon entry into the study they will be given in a blinded fashion one or more preventive doses of either Panhematin™ (4 mg/kg) or placebo, the number of which will correspond to the number of prophylactic doses they have been receiving within approximately one week for prophylaxis. A recurrent attack within the next 1, 2, 3 and 4 weeks will represent treatment failures. Because at study entry most subjects are expected to be on weekly prophylactic hemin treatment, and hemin is a short-acting drug, emphasis in the analysis will be on attacks occurring within 1 week after study treatment.

Any attacks that occur during the study will be treated according to standard of care, which may include Panhematin™, either at the study site or at a subject's usual treatment location.

It is intended that 20 subjects will complete treatment with blinded treatment and at least 4 weeks of follow up. A completed subject is one who meets all entrance criteria, has no exclusion criteria and completes the single dosing and at least one week of follow up, or is withdrawn because of an adverse event.